Tuesday, December 21, 2010

Women are more sensitive to stress, and therefore more likely to suffer from depression or PTSD, because of slight differences in male and female brains, according to new research.

From a recent Rutgers University press release:

Tracey Shors, a professor of psychology in Rutgers School of Arts and Sciences, has uncovered a clue to why men and women handle stress so differently in the brains of male and female rats.

The research, published Dec. 1 in the Journal of Neuroscience, has implications for the way stress-related disorders are treated in men and women.

Shors and her co-authors, graduate student Lisa Maeng and post-doctoral scholar Jaylyn Waddell, examined two brain regions important in learning and stress, the amygdala and the prefrontal cortex. The amygdala, a small almond-shaped structure located deep within the brain, senses stressful situations. The prefrontal cortex, in the front of the brain, is necessary for higher cognitive functions.

“These two structures are intimately connected to one another,” Shors said. “Therefore, we examined whether they communicate with one another to influence learning after stress.”

The researchers exposed male and female rats to stress, and then presented them with an associative learning task. During training, the rats learned to associate one event with another that occurred later in time. They played a tone and later stimulated the rats’ eyelids to elicit a blink. After the stimulus was taken away, most of the male rats responded to the tone by blinking on their own. Most of the females, however, did not blink in response to the tone, indicating that they had failed to learn that association. But the research also contained a neurological surprise for Shors, Maeng and Waddell.

When Shors and her colleagues disrupted the connections between the prefrontal cortex and the amygdala in some of the females, those females were able to learn the association.

“This wasn’t true for males," Shors said. "So, males and females are using different brain structures to learn after stress. In other words, females can learn after stress if the prefrontal cortex can’t ‘talk’ to the amygdala. From this, we conclude that males and females can use different brain circuits to learn after stressful life events.”